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Ultrastructural changes of cochlea in mice with hereditary chondrodysplasia (cho/cho)
1Department of Medicine, Microbiology, and Immunology, University of Tennessee, Memphis 38163.
Abstract:
Chondrodysplasia (cho/cho) is a recessive disorder in mice that affects cartilage important in the embryogenesis of cochlea. These mice show marked hearing loss when tested by auditory brain-stem responses. The temporal bone shows underdevelopment of the organs of Corti in the lower turn of the cochlea. Also, there are no supporting cells, inner or outer hair cells, nerve endings, or pillar cells. At the upper part of the cochlea, however, the organ of Corti is almost normal in structure. The exact nature of the molecular genetic abnormality that gives rise to the structural and functional cochlear anomalies seen in these mice is unknown.
Insights
Chondrodysplasia (cho/cho) in mice causes significant hearing loss due to underdeveloped cochlear cartilage. This genetic disorder affects the organ of Corti, leading to severe auditory defects.
Area of Science:
- Developmental biology
- Genetics
- Otolaryngology
Background:
- Chondrodysplasia (cho/cho) is a genetic disorder affecting cartilage development.
- Cartilage is crucial for cochlear embryogenesis.
- Mice with this mutation exhibit hearing loss.
Purpose of the Study:
- To investigate the structural and functional consequences of chondrodysplasia on the cochlea.
- To understand the impact of this genetic defect on hearing.
- To identify the molecular basis of cochlear anomalies in cho/cho mice.
Main Methods:
- Auditory brain-stem response testing to assess hearing.
- Temporal bone analysis to examine cochlear structure.
- Histological examination of the organ of Corti.
Main Results:
- Mice with chondrodysplasia show marked hearing loss.
- Underdevelopment of the organ of Corti in the lower cochlear turn.
- Absence of hair cells, nerve endings, and pillar cells in affected cochlear regions.
Conclusions:
- Chondrodysplasia leads to severe cochlear malformations and hearing impairment.
- The precise molecular genetic cause of these cochlear anomalies remains undetermined.
- Further research is needed to elucidate the genetic basis of chondrodysplasia-related hearing loss.